ERYTECH Pharma announced the allowance of a US patent application covering arginine deiminase (ADI) encapsulated into red blood cells for the treatment of arginase-1 deficiency (A1D), a debilitating rare metabolic disease. The claims will also cover methods of treating other indications, includingarginine-dependent cancers, septic shock, and angiogenesis-associated diseases. In addition to their potential in cancer metabolism, ERYTECH's red blood cell-encapsulated therapeutics can be deployed to reduce pathological levels of various metabolites, that can occur in certain inborn errors of metabolism disorders.

And while some enzyme replacement therapies (ERT) are commercially available, the clinical benefits of these enzymes are often outweighed by hypersensitivity and rapid clearance. Therefore, there is a high need for better tolerated and longer-acting ERT approaches. As disclosed in the recently allowed US 2020/0254074 A1 application, ERYTECH scientists evaluated the efficacy of red blood cell-encapsulated arginine deiminase (ERY-ADI) in a severe mouse model of A1D.

ERY-ADI not only reduced pathological levels of arginine in the blood (by >75%), but interestingly also did so without increasing serum ammonia. Moreover, one single administration of ERY-ADI reduced excess levels of blood arginine for at least 10 consecutive days. ERY-ADI also appeared to lower arginine levels in the liver where functioning arginase-1 is highly expressed, suggesting potential benefit in this setting characterized by an inherited deficiency in this enzyme.

These promising results, combined with ERYTECH's extensive experience with red blood cell-based therapeutics, support the potential for red blood cell-loaded enzymes to provide an improved therapeutic profile as compared with traditional ERT.